For motor vehicles with an electric drive, in particular for electric motor vehicles or hybrid electric motor vehicles, an electrical connection of electrical components of the motor vehicle, preferably of high-voltage components, to an energy supply unit, which is designed, in particular, as a rechargeable battery, preferably a high-voltage battery, is disconnected during an accident in order to prevent a short circuit due to damage to the motor vehicle caused by the accident, in particular a destruction or deformation thereof. A motor vehicle is understood, in particular, to be a passenger motor vehicle or a commercial vehicle. The electrical components of the kind addressed are, in particular, a drive of the motor vehicle and preferably other devices, in particular a power electronics unit of the motor vehicle. Preferably, an onboard power supply system of the motor vehicle, in particular a high-voltage onboard power supply system, via which the electrical components are supplied with energy, is thereby disconnected from the energy supply unit.
Typically, such a disconnection occurs by means of a switching device, which, for example, is designed as a contactor. It is also possible that the switching device is designed as pyrotechnic element, in particular within the energy supply unit. The switching device is actuated, as a rule, by way of an airbag control instrument. In an accident, the electrical components are typically under load when they are disconnected from the energy supply unit. In particular, for a design of the switching device as a contactor, this disconnection leads typically to arcing between contacts of the switching device, which causes a high wear. Furthermore, after the disconnection of the electrical connection, the motor vehicle either has to be restarted or has to be brought to a repair shop for renewed startup.
Because of such a limitation in an operation of the motor vehicle, typically a safety device, which brings about or initiates a disconnection of the electrical components, as a rule, has a very robust design, so in that a disconnection of the electrical components from the energy supply unit and consequently a deactivation of the onboard power supply system—in particular in regard to damage to the motor vehicle due to an accident—occurs relatively late in time. An accident detection in conjunction with such a safety device is made in this case typically by means of a sensor device, which, in particular, is provided for triggering restraint systems. On account of the addressed relatively late disconnection of the electrical components from the energy supply unit, these components are protected by means of complicated armoring against detrimental effects due to an accident, in particular when they can be damaged with a high probability during an accident, in order to prevent, in particular, the danger of a short circuit due to its effects.